The production of methyl chloroform -- 1,1,1-trichloroethane -- by the hydrochlorination of vinylidene chloride-1,1-dichloroethylene is well known. The basic process was described many years ago in the Nutting et al U.S. Pat. No. 2,209,000. In that patent, vinylidene chloride and hydrogen chloride are reacted under pressure in the presence of a Friedel-Crafts catalyst such as ferric chloride, maintaining the reaction at below 75.degree.C. The process is expensive to carry out commercially, since it is a pressure reaction. More recent workers -- see Vogt U.S. Pat. No. 3,065,280 and Dynamit Nobel German Pat. No. 1,231,226 -- have carried out the process at ambient pressures by suspending the catalyst in methyl chloroform, and passing the reactants into the mixture. The process works well, but the conversions obtained are rather poor, and catalyst activity falls off rapidly.